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Weak credential policy - Temporary passwords

Need​

Strengthening temporary password security policies

Context​

  • Usage of Go 1.16 for developing high-performance and efficient applications
  • Usage of gin-gonic/gin for building web applications and APIs in Go
  • Usage of net/http for creating HTTP servers in a Node.js application

Description​

Non compliant code​

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()

	r.POST("/reset_password", func(c *gin.Context) {
		tempPassword := c.PostForm("tempPassword")
		//...reset password logic
		c.JSON(http.StatusOK, gin.H{
			"message": "Password reset successful",
		})
	})

	r.Run()
}

The above code represents a password reset endpoint in a Go backend application using the Gin framework.

The vulnerability lies in the /reset_password endpoint. When a POST request is made to this endpoint, the application accepts a temporary password from the user in the tempPassword variable and uses it to reset the password.

The problem here is that there are no security policies in place for the temporary password. It could be any string the user chooses. This means the temporary password could be weak, easy to guess, or brute-force, thereby making the user's account susceptible to unauthorized access.

In a real-world scenario, an attacker could exploit this vulnerability by guessing or brute-forcing the temporary password, leading to potential unauthorized access to the user's account. This is a serious security issue as it directly compromises the privacy and integrity of the user's data.

To mitigate this vulnerability, the application should enforce a strong credential policy for temporary passwords. This can include a minimum length, requiring a mix of uppercase and lowercase letters, numbers, and special characters, and not allowing common or easily guessable passwords.

Steps​

  • Implement a strong password policy for temporary passwords.
  • Ensure that temporary passwords are randomly generated and not easily guessable.
  • Enforce a minimum password length and complexity requirements for temporary passwords.
  • Consider using a secure password hashing algorithm to store temporary passwords.
  • Implement a mechanism to expire temporary passwords after a certain period of time.
  • Provide a secure mechanism for users to change their temporary passwords to a permanent one.
  • Educate users about the importance of choosing strong passwords and the risks of using temporary passwords.

Compliant code​

package main

import (
	"crypto/rand"
	"encoding/base64"
	"github.com/gin-gonic/gin"
	"golang.org/x/crypto/bcrypt"
	"net/http"
	"time"
)

const (
	minPasswordLength = 10
	expirationTime    = 24 * time.Hour
)

func main() {
	r := gin.Default()

	r.POST("/reset_password", func(c *gin.Context) {
		tempPassword := generateTempPassword(minPasswordLength)
		hashedPassword, _ := bcrypt.GenerateFromPassword([]byte(tempPassword), bcrypt.DefaultCost)

		//...reset password logic using hashedPassword
		//...store the expiration time of the temporary password

		c.JSON(http.StatusOK, gin.H{
			"message": "Password reset successful",
		})
	})

	r.Run()
}

func generateTempPassword(length int) string {
	buff := make([]byte, length)
	rand.Read(buff)
	str := base64.StdEncoding.EncodeToString(buff)
	// Cut the length if it's more than length
	return str[:length]
}

The updated code includes a function to generate a temporary password that is randomly generated and not easily guessable. The generateTempPassword function generates a random string of a specified length. This string is then hashed using the bcrypt algorithm, which is a secure password hashing algorithm.

The temporary password is then used in the password reset logic. The hashed password should be stored, not the plain text temporary password. Also, an expiration time for the temporary password should be stored to ensure that the temporary password expires after a certain period of time.

The constant minPasswordLength is used to enforce a minimum password length. The expirationTime constant is used to set the expiration time for the temporary password.

This code does not include the mechanism for users to change their temporary password to a permanent one. This would need to be implemented in the password reset logic.

Finally, it's important to educate users about the importance of choosing strong passwords and the risks of using temporary passwords. This could be done through user interface messages, documentation, or other forms of communication.

References​

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